Balloon envelope material and meth



March 3, 1936. T' B-L 2,032,857

BALLOON ENVELOPE MATERIAL AND METHOD OF MANUFACTURING THE ,SAME

Filed Jan. 24, 1935 Invenfar:

Patented Mar. 3, 1936 PATENT OFFICE BALEooN ENVELOPE MATERIAL AND METH-on or MANUFACTURING THE sAME Hans Strobl, Berlin-Tempelhof, Germany, as-

signor to Luftsizhiffbau Zeppelin G. m. 'b. H., Fiiedrichshafen,Bodensee, Germany Application January 24, 1935, Serial No. 3,360 -InGermany June 23, 1930 4 Claims. (o1. 154-2) .My-invention relates toballoon envelope materialas-for example for gas cells of gas inflatedairships and the like and to the method of manufacturing such material..The present application is a continuation in part of my applicationSerial No. 544,167, filed June 13, 193 1.

Lately ithas become usual to-manufacture balloon envelope material fromfabric combined with skins of animal provenience, both materials beingglued together by an adhesive comprising gelatine; isinglass or similarsubstances with an admixture of softening substances such asglycerine,-Turkey red oil orthe like. According to my invention I useonly staple fabric without any animal skins or the like,but I impregnatethe fabric with liquid substances only. First I impregnate the fabricwith a substance insoluble in water, such' asindia rubber solution, acellulose product, for instance cellulose acetate or cellulose nitrate,or the like. This impregnation rendering the fabric resistant againstweather influences may be applied to the fabric from one. side only orfrom both sides; I prefer to impregnate from one side only but to havethe interstices of the fabric filled more or less with this firstimpregnation substance. Nor-' mally the amount of substance appliedtothe fabric should be such that an uninterrupted surface layer of suchwaterproof material results. Of course, instead of substances entirelyinsoluble in water such substances may be used also E1011 arenearly'insoluble or mixtures of both ingagent such as glycerine, Turkeyred oil or Then I provide one side of the impregnated fabric with asecond impregnation, this' time composed of gelatine, of casein,isinglass ora similar substance with an admixture of a soften.-

the like. These substances may be applied-as a mixture or separately in'anynumber. of coatings. The weight proportion of the gelatinous materialto the softening agent "should be from 50:50 to" 33%;:66%, which meansthat at least the same weight amount ofsoftening agent should be appliedas gelatinous material is used. flhissecond' impregnation which is tobemade on the second surface of the fabric may again be applied in such'quantitythat a second uninterrupted surface layer of such gastighteningsubstances results. 7 I

At last I add to the material which is now impregnated twice a thirdlayer preferably of fibre or the like, whichisconnected to the otherlayers by means of'the impregnating substancesthemselves, which can bedone by applyingtlns fibre substance for the second impregnation.

.' This second impregnation which is-hygroscopic layer before the priorimpregnations have dried, or any well-known adhesive may be usedtherefor. This layer of fibre may be applied loosely or as a fabric, ascircumstances may .aiford. Cotton or linen fibre for example aresuitable. for this layer. This fibre layer can be applied toone side orto both sides of the balloon envelope material; if applied to one sideonly it should be the side which carries the second (gastightening)impregnation, as this needs protection more than the weather=proofsurface.

As the first impregnation for rendering the original fabric resistantagainst weather-influences serves more or less also for filling theinterstices of the fabric, this means a reduction in the necessaryamount of the gas-tighte1 1]i;11ge third'layer consisting of fibre ismost important because it protects the impregnation layer or layersagainst influences from outside, especially Q0 mechanical influencessuch as rubbing and the like. It is very valuable to have suchprotection on the side of the second (gas-tight) impregnation, but ifcircumstances should afiord both sides may be so protected.

The new material attained by my method of manufacture has greatadvantages over the old the. material resistant against-weather influ- 3ences and then both may be united by means of an intermediateimpregnation of the second kind for making the material gas-tightserving at the same time for gluing the two layers together.

is thenv enclosed by the weather-resistant coatings so that practicallya minimum of water 1 can "only be absorbed.

To the impregnating substances which are subject to decomposition byouter influences 45 (substances: of animal provenience as gelatine Y orthe like) I prefer to. make "a preserving agent,. as forinstancecreosote or-the like.

In certain cases it may be found desirable'to further .add tothe balloonenvelope material '50 manufactured according to the new method of myinvention-as explained abovean outer coating ofoil or lacquer, which maybe applied a in any well-known manner on top of the fibrous layer and/oron the surface which possibly does 55 quantity of the impregnatingsubstance is assumed to be so rich that the upper surface of theimpregnating layer is plane. But of course, in

certain cases it may suffice to apply only so much material that thefabric l is just soaked up toits upper surface so that the surface ofthe impregnation is wave-like following-the surface of the fabricitself; The second impregnation 3 of the gas-proofing composition isapplied to the other side of the fabric. There is a protective layer offibre 4 assumed to be applied to .both sides of the balloon material.

I do not want to be limited to the detailsdescribed or shown in thedrawing as many variations will occur to those skilled in the art.

What I claim is:

1. Balloon envelope material comprising a water-proofed staple fabric, agas-proofing gelatinous coating including a softening agent and havingadhesive properties applied to the side of said fabric, and awear-resisting layer of fibre secured to the fabric on the gas-proofedside thereof. u

.2. Method ofwmanufacturing weather-proof and gas-tight balloon envelopematerial which consists in first impregnating a staple "fabric with aliquid water-proofing composition, then applying a gas-proofinggelatinous composition coating to one side of the fabric, and thereafterafilxing swear-resisting fibrous layer to the gas-proofed side of thefabric.

3. Method of, manufacturing weather-proof and gas-tight balloon envelopematerial which .consists in first impregnating a, staple fabric from oneside with a liquid weather-proofing composition,-then applying on theother-side a gas-proofing'impregnation of gelatinous coating materialincorporatingv a softening agent; and

thereafter afiixing a protective fibrous layer to the gas-proofed sideof the fabric.

4. Method of (manufacturing weather-proof and gas-tight balloon envelopematerial which consists in first impregnating a staple fabric from oneside with a weather-proofing liquid rubber composition; then applying onthe other side a gas-proofing impregnation of gelatinous coatingmaterial incorporating a softening agent and having adhesive properties,and afiixing to the gas-proofing impregnation through itsadhesive.properties a protective fibrous layer.

HANS STROIVBL.

